Miniature positive action toggle switch

ABSTRACT

A snap-action toggle switch of the positive action type. That is, after the toggle lever has been moved to load the drive spring, a direct driving connection from the toggle lever to the contacts forces contact movement in the event they stick together. The drive spring then causes snap-action movement of the switch contacts. The return spring and drive spring mechanisms are designed to fit into a smaller space to provide a miniature switch. The switch positioning, spring-biased plunger mechanism is designed for optimum trip point relative to contact operation for nonteasing switch operation.

United States Patent Hults [451 Jan. 18, 1972 [54] MINIATURE POSITIVE ACTION TOGGLE SWITCH [72] Inventor: Harold W. Hulls, New Berlin, Wis.

[73] Assignee: Cutler-Hammer, Inc., Milwaukee, Wis.

[22] Filed: Feb. 26, 1970 [21] Appl. No.: 14,446

3,485,966 12/1969 Bailey et a1. ..200/l6 OTHER PUBLICATIONS Cutler-Hammer, Positive Action Miniature Military Switches, Received Patent Office Sept. 25, 1959. 6 pp.

Primary Examiner-David Smith, Jr. Attorney-Hugh R. Rather ABSTRACT A snap-action toggle switch of the positive action type. That is, after the toggle lever has been moved to load the drive spring, a direct driving connection from the toggle lever to the contacts forces contact movement in the event they stick together. The drive spring then causes snap-action movement of the switch contacts. The return spring and drive spring mechanisms are designed to fit into a smaller space to provide a miniature switch. The switch positioning, spring-biased plunger mechanism is designed for optimum trip point relative to contact operation for nonteasing switch operation.

10 Claims, 7 Drawing Figures ill.

l ill I PATENTED JAN] 8 I972 sum 1 pr 2 M a m/ 6 11 zmmm m] 4 3 v! 8 m f z 6 8 1 3 m 0 a n 8 8 Z 4 M. i n a 7 H W c 8 I 6.. 2w. 7 4 33 6 5 8 4 I/ V/E I .fhtamey PATENTEB JAN18I972 3"6352 6 MINIATURE POSITIVE ACTION TOGGLE SWITCH BACKGROUND OF THE INVENTION Positive action toggle switches have been known heretofore. Positive action refers to an unyielding driving connection from the operating lever to the movable contact for at least a portion of the operating stroke to force opening of sticking contacts. These positive action toggle switches have also included a snap-action mechanism for fast contact operation. For this purpose, a drive spring is loaded during the first part of the operating stroke andthe positive action mechanism then engages to start the contact operation and to release the positioning mechanism. The drive spring then snaps the contact to the new position wherein the positioning mechanism retains the switch.

While these prior switches have been useful for their intended purposes, this invention relates to improvements thereon.

SUMMARY OF THE INVENTION This invention relates to improvements in positive action toggle switches that enhance performance including nonteasing contact operation and contribute to miniaturization of the switch.

An object of the invention is to provide an improved positive action switch.

A more specific object of the invention is to provide an improved positive action switch structure of the snap-action type that affords construction of the switch in a miniature size.

Another specific object of the invention is to provide an improved positive action switch structure of the momentary type that affords construction of the switch in a miniature size.

Another specific object of the invention is to provide an improved positive action switch structure of the momentary type that affords construction of the switch in a miniature size.

Another specific object of the invention is to provide an improved snap-action switch structure that effectively prevents teasing the contacts.

Another specific object of the invention is to provide an improved positive action switch structure of the snap-action momentary type that affords construction of the switch in a miniature size.

Another specific object of the invention is to provide an improved snap-action switch structure that affords preselection of the trip point in advance of contact operation to prevent teasing.

Other objects and advantages of the invention will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an enlarged isometric view of the miniature positive action toggle switch constructed in accordance with the invention;

FIG. 2 shows a further enlarged cross-sectional view of the switch taken along line 22 of FIG. 3;

FIG. 3 shows a lateral sectional view of the switch taken along line 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken along line 44 of FIG. 3 to show the return spring mechanism of the switch;

FIG. 5 is a fragmentary sectional view taken along line 55 of FIG. 3 to show the drive spring mechanism and positioning plunger mechanism of the switch; and

FIGS. 6 and 7 are still more enlarged isometric views of the drive plate and actuator block, respectively, of the switch.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a miniature positive action toggle switch constructed in accordance with the invention. The single-pole double-throw switch shown and described can be made as small as 9/16 by 13/32 inches maximum dimensions and 1% inches high, approximately.

While a single-pole switch has been used to illustrate the invention, the structure disclosed herein can be used for other types of multipole switches such as a double-pole doublethrow type, for example. While the single-pole version has a switch mechanism at the left as shown in FIG. 3 and a positioning mechanism at the right, the double-pole version or three-pole, four-pole, etc., requires only duplication of the switch mechanism on the opposite side of the positioning mechanism. As a result, the positioning mechanism is in the middle and the switch mechanisms are on opposite sides thereof in the double-pole double-throw version. With use of the structure disclosed herein the double-pole double-throw switch can be made correspondingly small, approximately 9/ l6 by 9/16 inches maximum dimensions and 1% inches high.

The switch shown in FIG. 1 is provided with a housing including an insulating base 2 having an open top that is closed by a metal frame 4. This frame is provided with a bushing 4a through which extends the operating handle of an operating lever 6. Three spaced-apart terminals 8 extend out through the bottom of the base and are adapted for connecting the switch to an external circuit. Bushing 4a is provided with a flange 4b at its lower end secured to the upper surface of the frame as by spot welding to center the bushing on the frame. The upper peripheral portion of this flange is provided with a circular channel adapted to receive an O-ring to seal the switch to a panel on which it is mounted. For this purpose, the bushing is externally threaded to receive a nut to mount the switch by its bushing in a hold in the panel. A positioning plate 4d is welded to one side of the frame and is provided with a notch for engaging a protuberance on the mounting panel thereby to facilitate mounting the switch in the correct direction.

Terminals 8 have stationary contacts integral therewith within the base as shown in FIGS. 2 and 3. To fix the terminals within the base, the stationary contact portion of each one has a pair of tabs 8a bent laterally in opposite directions as shown in FIG. 2. This allows the terminals to be inserted from within the base through the openings in the bottom until these tabs bear against the inner bottom of the base. The two external edges are clinched against the outer bottom of the base as shown in FIG. 3 to hold the terminals in place. And the terminal is sealed to the base bysuitable compounds.

The operating lever is mounted for pivotal movement in the bushing and is sealed. For this purpose, the bushing is provided at its upper portion with an internal flange as shown in FIG. 2 against which the spherical portion of the operating lever bears when the handle is inserted through the bushing from below. An annular seal 10 surrounds the spherical por tion of the operating lever and a retaining bushing 12 compresses the seal between itself and the bushing including its in,- temal flange and the spherical portion of the operating lever. This retaining bushing is shaped so that it diverges downwardly to allow space for the lower end of the operating lever to swing from one side to the other.

The base of the switch is provided with two compartments as shown in FIG. 3 to enclose the switch mechanism and the positioning mechanism, respectively.

The switch mechanism within the left-hand compartment in FIG. 3 comprises an actuating lever 14 more clearly shown in FIG. 2. This actuating lever is a flat, generally anchor-shaped member having a vertical stem and a pair of feet extending laterally in opposite directions. The upper end of the stem is rounded for pivoting in a complementary recess in actuator block 16. A notch is provided at the lower end between the heels of the two feet by which theactuating lever is held on and pivots on the central stationary contact.

The switch mechanism also comprises a contactor such as a movable contact 18. This movable contact is a flat strip having an aperture at the middle through which the stem of the actuating lever is inserted so that opposite portions of the movable contact rest on the feet thereof. The opposite ends of the contactor are reduced in width so that they will not engage the bent tabs on the stationary contacts. A frustoconical, helical spring surrounds the stem of the actuating lever and is compressed between the actuator block and the contactor to provide suitable contact pressure, there being a boss on the actuator block around the actuating lever recess for retaining the larger end of this compression spring.

The positioning plunger mechanism in the right-hand compartment in FIG. 3 comprises a generally E-shaped plunger 22, as shown in FIG. 5, lying down to accommodate two helical bias springs 24 in the spaces between the arms of the plunger and compressed between this plunger and the bottom of the compartment. The back of the E-shaped plunger has two spaced peaked projections 22a biased into complementary positioning notches in the bottom of the actuator block. As shown in FIG. 5, five such notches are spaced on the actuator block so that the plunger will stop the actuator block in any one of three selected positions including the center ofi' position shown wherein the plunger engages the second and fourth notches and left and right positions wherein the plunger engages the first and third or third and fifth notches and the centralstationary contact is bridged to the left or the right stationary contact, respectively, as shown in FIG. 2.

A drive mechanism and return mechanism are provided between the operating lever and the actuator block to cause positive action, snap-action movement of the actuator block from the center. off position shown in FIG. 2 to either operating position and back again. These mechanisms involve certain configurations in the upper surface of the actuator block and the lower surface of a drive plate 26 as shown in FIGS. 6 and 7.

The drive mechanism comprises a rectangular recess 16a centrally disposed on the upper surface of the actuator block for receiving a relatively shorter rectangular projection 26a extending down from the lower surface of the drive plate. This structure constitutes the positive action coupling. It can-be seen in FIGS. 2, 6 and 7 that if the drive plate is moved either to the left or to the right from its center position, a predetermined amount of lost motion will be taken up whereafter the drive plate will positively force the actuator block to move. This lost motion will be used to compress the drive spring as hereinafter described. Also, when the switch is in one of its operating positions, this positive engagement enables the drive plate to force the actuator block from an end position to the center position. This positive movement will cause the contact actuator to pry the contactor loose from the stationary contact in the event they become welded together.

The drive mechanism also comprises an elongated channel 16b at one side of recess 16a in the upper surface of the actuator block for retaining a helical drive spring 28. Narrower grooves 160 extend from each end of channel 16b out through the opposite ends of the actuator block for slidably accommodating fingers 26b of the drive plate as shown in FIG. 5. These fingers are spaced apart a distance substantially equal to the length of channel 16b so that they abut opposite ends of the drive spring when the switch is in its center off position. From this it can be seen that movement of the drive plate in either lateral direction relative to the actuator block causes one of the fingers 26b to compress the corresponding end of the drive spring. This comes about because the other end of the drive spring is stopped against the other end of channel 16b in the actuator block. I

This drive spring is compressed until the positive action coupling hereinbefore described engages to move the actuator block. The notches in the bottom of the actuator block then cam down the positioning plunger until its projections become clear thereof. At this time, the drive spring snaps the actuator block to complete its switch operating movement with a fast action.

The aforesaid return spring mechanism that is located between the operating lever and the actuator block is shown in FIGS. 4, 6 and 7. This mechanism comprises an elongated channel 260 in the drive plate for retaining a helical return spring 30. This channel is located on the opposite side of positive action projection 26a from snap action fingers 26b as shown in FIGS. 3 and 6. Narrower grooves 26d extend from each end of channel 26c out through the opposite ends of the drive plate for slidably accommodating return plungers 32. As shown in FIG. 4, each return plunger 32 has a flange or annular ridge 32a that abuts the end of channel 26c to limit its outward movement. This ridge is spaced from the inner end of the return plunger enough to provide an end portion projecting into the corresponding end of return spring 30 to hold the spring on the plunger. The ends of this return spring abut the annular ridges on the two return plungers and bias them outwardly against their stops. The outer ends of the return plungers extend out from grooves 26d beyond the ends of the drive plate into close proximity with the inner wall of switch frame 4.

7 From the foregoing, it will be apparent that when the switch is operated to move the drive plate, one of the return plungers 32 will not move because its outer end abuts the frame. Consequently, this return plunger will compress the return spring. And when the switch operating handle is released, the return spring will move the drive plate back to its center off position. Using a single return spring 30 and two plungers affords construction of a return mechanism having a shorter overall length than prior devices using two return springs. This shorter length is obtained without sacrificing the resilient length of the spring tat is required for the drive plate movement necessary in the switch.

The arrangement of a return spring and two return plungers shown in FIG. 4 provides momentary action in both directions of switch operation. If momentary action is desired only in one direction, it can be obtained readily by omitting one return plunger.

The drive spring mechanism using a single spring 28 for both directions of movement hereinbefore described also affords construction of a drive spring mechanism having a shorter overall length over two spring mechanisms as in the prior art.

The nonteasing feature is easily provided by making flats 22b at the peaks of the positioning plunger projections 22a. 'Ihese flats prevent the contacts from starting to open before the snap-action movement starts thereby to prevent teasing of the contacts. The larger that these flats are made by cutting off more of the projection, the sooner the snap-action movement will start relative to contact operation. Consequently, the trip point of the snap-action movement can be set as desired by providing the proper flats on the positioning plunger.

While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiment of miniature positive action toggle switch disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the ap pended claims.

I claim:

I. In a miniature electric switch, the combination comprisa housing including an insulating base; stationary contacts within said base and having tenninals outside the base adapted to be connected to an external circuit;

a movable contact within said base;

and contact actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising:

an actuator block member mounted for sliding movement along said base into a plurality of different operating positions;

means coupling said actuator block member to said movable contact;

and snap action means for moving said actuator block member from one of said operating positions to another to close or open the contacts comprising:

positioning means for resiliently biasing said actuator block member into each of its operating positions when it is moved thereto including means for preventing teasing of the contacts comprising:

a spring-biased positioning plunger held in a compartment in the base and having a peaked cam follower portion projecting from the base into engagement with a complementary camming notch in the actuator block member for each operating position of the latter.

and said cam follower portion being provided with a flat to shorten its peak sufficiently to set a predetermined pointat which the positioning plunger releases the actuator block relative to contact operation to insure that the snap action movement starts before the contacts start to open thereby to prevent teasing the contacts.

2. The invenfion defined in claim 1, wherein said snap-action means also comprises:

a drive plate member laterally movable relative to said actuator block member;

a drive spring channel in one of said members and relatively smaller grooves extending from the ends of said channel through said one member;

a drive spring in said channel;

and a pair of abutments projecting from the other member into said grooves adjacent the opposite ends of said drive spring to compress the latter when the switch is operated and to cause snap-action operation when the positioning plunger is cammed out of its complementary notch.

3. The invention defined in claim 2, wherein said actuator block member and said drive plate member comprise:

a lost motion coupling affording limited relative motion therebetween for compression of said drive spring and positive engagement therebetween thereafter to provide positive action for operation of the contacts.

4. The invention defined in claim 1, wherein said snap-action means also comprises:

a drive plate movable relative to said actuator block;

a drive spring channel in said actuator block and relatively smaller grooves extending out from the ends of said channel;

a drive spring confined in said channel;

and a pair of projections integral with said drive plate and extending into said grooves at the opposite ends of said drive spring for compressing the latter when the switch is operated to cause snap action movement of the movable contact.

5. The invention defined in claim 4, wherein said drive spring is a helical spring in compression within said drive spring channel.

6. The invention defined in claim 5, wherein said contactactuating means also comprises:

a toggle lever pivotally supported in said housing for moving said drive plate from a center off position in opposite directions to operation positions.

7. ln a miniature electric switch, the combination comprising:

a housing including an insulating base;

stationary contacts within said base and having terminals outside the base adapted to be connected to an external circuit;

a movable contact within said base;

and contact-actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising:

a laterally movable drive plate;

a channel in said drive plate and relatively smaller grooves extending from the ends of said channel through said drive plate;-

a return spring in said channel;

and at least one return plunger having a shoulder thereon biased against one end of said channel by said return spring and having an elongated stem extending through the adjacent groove into close proximity with a wall of the housing when the switch is in its off position, said return plunger abutting said wall to compress said retun spring when the swrtc lS actuated to its operating position to provide a momentary switch.

8. The invention defined in claim 7, wherein said contact actuating means also comprises:

an actuator block slidable on said base;

a positive action, limited lost motion connection between said drive plate and said actuator block;

and an actuating lever movable by said actuator block for moving said movable contact.

9. The invention defined in claim 8, wherein said contact actuating means further comprises:

a means for causing snap-action movement of the movable contact comprising:

spring-biased positioning means for resiliently holding said actuator block in any of its positions;

and drive spring means including an elongated pocket in said actuator block confining a helical drive spring and a pair of projections on said drive plate embracing the ends of said drive spring and effective to compress it against either end of its pocket during initial movement of said drive plate while said lost motion is taken up.

10. In a miniature electric switch, the combination comprisa housing including an insulating base;

stationary contacts within said base and having terminals outside the base adapted to be connected to an external circuit;

a movable contact within said base;

and contact-actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising:

an actuator block member mounted for sliding movement along said base into a plurality of different operating positions;

means coupling said actuator block member to said movable contact;

and snap-action means for moving said actuator block member from one of said operating position to another to close or open the contacts comprising:

positioning means for resiliently biasing said actuator block member into each of its operating positions when it is moved thereto;

a drive plate member laterally movable relative to said actuator block member;

a drive spring channel in one of said members and relatively smaller grooves extending from the ends of said channel through said one member;

a drive spring in said channel;

and a pair of abutments projecting from the other member into said grooves adjacent the opposite ends of said drive spring to compress the latter when the switch is operated and to cause snap-action operation when said resiliently biased positioning means is released. 

1. In a miniature electric switch, the combination comprising: a housing including an insulating base; stationary contacts within said base and having terminals outside the base adapted to be connected to an external circuit; a movable contact within said base; and contact actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising: an actuator block member mounted for sliding movement along said base into a plurality of different operating positions; means coupling said actuator block member to said movable contact; and snap action means for moving said actuator block member from one of said operating positions to another to close or open the contacts comprising: positioning means for resiliently biasing said actuator block member into each of its operating positions when it is moved thereto including means for preventing teasing of the contacts comprising: a spring-biased positioning plunger held in a compartment in the base and having a peaked cam follower portion projecting from the base into engagement with a complementary camming notch in the actuator block member for each operating position of the latter, and said cam follower portion being provided with a flat to shorten its peak sufficiently to set a predetermined point at which the positioning plunger releases the actuator block relative to contact operation to insure that the snap action movement starts before the contacts start to open thereby to prevent teasing the contacts.
 2. The invention defined in claim 1, wherein said snap-action means also comprises: a drive plate member laterally movable relative to said actuator block member; a drive spring channel in one of said members and relatively smaller grooves extending from the ends of said channel through said one member; a drive spring in said channel; and a pair of abutments projecting from the other member into said grooves adjacent the opposite ends of said drive spring to compress the latter when the switch is operated and to cause snap-action operation when the positioning plunger is cammed out of its complementary notch.
 3. The invention defined in claim 2, wherein said actuator block member and said drive plate member comprise: a lost motion coupling affording limited relative motion therebetween for compression of said drive spring and positive engagement therebetween thereafter to provide positive action for operation of the contacts.
 4. The invention defined in claim 1, wherein said snap-action means also comprises: a drive plate movable relative to said actuator block; a drive spring channel in said actuator block and relatively smaller grooves extending out from the ends of said channel; a drive spring confined in said channel; and a pair of projections integral with said drive plate and extending into said grooves at the opposite ends of said drive spring for compressing the latter when the switch is operated to cause snap action movement of the movable contact.
 5. The invention defined in claim 4, wherein said drive spring is a helical spring in compression within said drive spring channel.
 6. The invention defined in claim 5, wherein said contact-actuating means also comprises: a toggle lever pivotally supported in said housing for moving said drive plate from a center off position in opposite directions to opeRation positions.
 7. In a miniature electric switch, the combination comprising: a housing including an insulating base; stationary contacts within said base and having terminals outside the base adapted to be connected to an external circuit; a movable contact within said base; and contact-actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising: a laterally movable drive plate; a channel in said drive plate and relatively smaller grooves extending from the ends of said channel through said drive plate; a return spring in said channel; and at least one return plunger having a shoulder thereon biased against one end of said channel by said return spring and having an elongated stem extending through the adjacent groove into close proximity with a wall of the housing when the switch is in its off position, said return plunger abutting said wall to compress said return spring when the switch is actuated to its operating position to provide a momentary switch.
 8. The invention defined in claim 7, wherein said contact actuating means also comprises: an actuator block slidable on said base; a positive action, limited lost motion connection between said drive plate and said actuator block; and an actuating lever movable by said actuator block for moving said movable contact.
 9. The invention defined in claim 8, wherein said contact actuating means further comprises: a means for causing snap-action movement of the movable contact comprising: spring-biased positioning means for resiliently holding said actuator block in any of its positions; and drive spring means including an elongated pocket in said actuator block confining a helical drive spring and a pair of projections on said drive plate embracing the ends of said drive spring and effective to compress it against either end of its pocket during initial movement of said drive plate while said lost motion is taken up.
 10. In a miniature electric switch, the combination comprising: a housing including an insulating base; stationary contacts within said base and having terminals outside the base adapted to be connected to an external circuit; a movable contact within said base; and contact-actuating means for operating said movable contact into and out of engagement with said stationary contacts comprising: an actuator block member mounted for sliding movement along said base into a plurality of different operating positions; means coupling said actuator block member to said movable contact; and snap-action means for moving said actuator block member from one of said operating position to another to close or open the contacts comprising: positioning means for resiliently biasing said actuator block member into each of its operating positions when it is moved thereto; a drive plate member laterally movable relative to said actuator block member; a drive spring channel in one of said members and relatively smaller grooves extending from the ends of said channel through said one member; a drive spring in said channel; and a pair of abutments projecting from the other member into said grooves adjacent the opposite ends of said drive spring to compress the latter when the switch is operated and to cause snap-action operation when said resiliently biased positioning means is released. 